X-Git-Url: http://git.cascardo.info/?a=blobdiff_plain;f=net%2Fcore%2Fpktgen.c;h=8b849ddfef2e743676fe35642cd49d36188dd74d;hb=a1b0a006ea7eb0c272cef33740a9563cd5190974;hp=fc17a9d309ac028fc61ac7db6e35a05c77513a24;hpb=66a521bdda5681db255d4ce323c0de1a30e08f04;p=cascardo%2Flinux.git diff --git a/net/core/pktgen.c b/net/core/pktgen.c index fc17a9d309ac..8b849ddfef2e 100644 --- a/net/core/pktgen.c +++ b/net/core/pktgen.c @@ -69,8 +69,9 @@ * for running devices in the if_list and sends packets until count is 0 it * also the thread checks the thread->control which is used for inter-process * communication. controlling process "posts" operations to the threads this - * way. The if_lock should be possible to remove when add/rem_device is merged - * into this too. + * way. + * The if_list is RCU protected, and the if_lock remains to protect updating + * of if_list, from "add_device" as it invoked from userspace (via proc write). * * By design there should only be *one* "controlling" process. In practice * multiple write accesses gives unpredictable result. Understood by "write" @@ -208,7 +209,7 @@ #define T_REMDEVALL (1<<2) /* Remove all devs */ #define T_REMDEV (1<<3) /* Remove one dev */ -/* If lock -- can be removed after some work */ +/* If lock -- protects updating of if_list */ #define if_lock(t) spin_lock(&(t->if_lock)); #define if_unlock(t) spin_unlock(&(t->if_lock)); @@ -241,6 +242,7 @@ struct pktgen_dev { struct proc_dir_entry *entry; /* proc file */ struct pktgen_thread *pg_thread;/* the owner */ struct list_head list; /* chaining in the thread's run-queue */ + struct rcu_head rcu; /* freed by RCU */ int running; /* if false, the test will stop */ @@ -802,7 +804,6 @@ static int strn_len(const char __user * user_buffer, unsigned int maxlen) case '\t': case ' ': goto done_str; - break; default: break; } @@ -1737,14 +1738,14 @@ static int pktgen_thread_show(struct seq_file *seq, void *v) seq_puts(seq, "Running: "); - if_lock(t); - list_for_each_entry(pkt_dev, &t->if_list, list) + rcu_read_lock(); + list_for_each_entry_rcu(pkt_dev, &t->if_list, list) if (pkt_dev->running) seq_printf(seq, "%s ", pkt_dev->odevname); seq_puts(seq, "\nStopped: "); - list_for_each_entry(pkt_dev, &t->if_list, list) + list_for_each_entry_rcu(pkt_dev, &t->if_list, list) if (!pkt_dev->running) seq_printf(seq, "%s ", pkt_dev->odevname); @@ -1753,7 +1754,7 @@ static int pktgen_thread_show(struct seq_file *seq, void *v) else seq_puts(seq, "\nResult: NA\n"); - if_unlock(t); + rcu_read_unlock(); return 0; } @@ -1878,10 +1879,8 @@ static struct pktgen_dev *__pktgen_NN_threads(const struct pktgen_net *pn, pkt_dev = pktgen_find_dev(t, ifname, exact); if (pkt_dev) { if (remove) { - if_lock(t); pkt_dev->removal_mark = 1; t->control |= T_REMDEV; - if_unlock(t); } break; } @@ -1931,7 +1930,8 @@ static void pktgen_change_name(const struct pktgen_net *pn, struct net_device *d list_for_each_entry(t, &pn->pktgen_threads, th_list) { struct pktgen_dev *pkt_dev; - list_for_each_entry(pkt_dev, &t->if_list, list) { + rcu_read_lock(); + list_for_each_entry_rcu(pkt_dev, &t->if_list, list) { if (pkt_dev->odev != dev) continue; @@ -1946,6 +1946,7 @@ static void pktgen_change_name(const struct pktgen_net *pn, struct net_device *d dev->name); break; } + rcu_read_unlock(); } } @@ -2997,8 +2998,8 @@ static void pktgen_run(struct pktgen_thread *t) func_enter(); - if_lock(t); - list_for_each_entry(pkt_dev, &t->if_list, list) { + rcu_read_lock(); + list_for_each_entry_rcu(pkt_dev, &t->if_list, list) { /* * setup odev and create initial packet. @@ -3007,18 +3008,18 @@ static void pktgen_run(struct pktgen_thread *t) if (pkt_dev->odev) { pktgen_clear_counters(pkt_dev); - pkt_dev->running = 1; /* Cranke yeself! */ pkt_dev->skb = NULL; pkt_dev->started_at = pkt_dev->next_tx = ktime_get(); set_pkt_overhead(pkt_dev); strcpy(pkt_dev->result, "Starting"); + pkt_dev->running = 1; /* Cranke yeself! */ started++; } else strcpy(pkt_dev->result, "Error starting"); } - if_unlock(t); + rcu_read_unlock(); if (started) t->control &= ~(T_STOP); } @@ -3041,27 +3042,25 @@ static int thread_is_running(const struct pktgen_thread *t) { const struct pktgen_dev *pkt_dev; - list_for_each_entry(pkt_dev, &t->if_list, list) - if (pkt_dev->running) + rcu_read_lock(); + list_for_each_entry_rcu(pkt_dev, &t->if_list, list) + if (pkt_dev->running) { + rcu_read_unlock(); return 1; + } + rcu_read_unlock(); return 0; } static int pktgen_wait_thread_run(struct pktgen_thread *t) { - if_lock(t); - while (thread_is_running(t)) { - if_unlock(t); - msleep_interruptible(100); if (signal_pending(current)) goto signal; - if_lock(t); } - if_unlock(t); return 1; signal: return 0; @@ -3166,10 +3165,10 @@ static int pktgen_stop_device(struct pktgen_dev *pkt_dev) return -EINVAL; } + pkt_dev->running = 0; kfree_skb(pkt_dev->skb); pkt_dev->skb = NULL; pkt_dev->stopped_at = ktime_get(); - pkt_dev->running = 0; show_results(pkt_dev, nr_frags); @@ -3180,9 +3179,8 @@ static struct pktgen_dev *next_to_run(struct pktgen_thread *t) { struct pktgen_dev *pkt_dev, *best = NULL; - if_lock(t); - - list_for_each_entry(pkt_dev, &t->if_list, list) { + rcu_read_lock(); + list_for_each_entry_rcu(pkt_dev, &t->if_list, list) { if (!pkt_dev->running) continue; if (best == NULL) @@ -3190,7 +3188,8 @@ static struct pktgen_dev *next_to_run(struct pktgen_thread *t) else if (ktime_compare(pkt_dev->next_tx, best->next_tx) < 0) best = pkt_dev; } - if_unlock(t); + rcu_read_unlock(); + return best; } @@ -3200,13 +3199,13 @@ static void pktgen_stop(struct pktgen_thread *t) func_enter(); - if_lock(t); + rcu_read_lock(); - list_for_each_entry(pkt_dev, &t->if_list, list) { + list_for_each_entry_rcu(pkt_dev, &t->if_list, list) { pktgen_stop_device(pkt_dev); } - if_unlock(t); + rcu_read_unlock(); } /* @@ -3220,8 +3219,6 @@ static void pktgen_rem_one_if(struct pktgen_thread *t) func_enter(); - if_lock(t); - list_for_each_safe(q, n, &t->if_list) { cur = list_entry(q, struct pktgen_dev, list); @@ -3235,8 +3232,6 @@ static void pktgen_rem_one_if(struct pktgen_thread *t) break; } - - if_unlock(t); } static void pktgen_rem_all_ifs(struct pktgen_thread *t) @@ -3248,8 +3243,6 @@ static void pktgen_rem_all_ifs(struct pktgen_thread *t) /* Remove all devices, free mem */ - if_lock(t); - list_for_each_safe(q, n, &t->if_list) { cur = list_entry(q, struct pktgen_dev, list); @@ -3258,8 +3251,6 @@ static void pktgen_rem_all_ifs(struct pktgen_thread *t) pktgen_remove_device(t, cur); } - - if_unlock(t); } static void pktgen_rem_thread(struct pktgen_thread *t) @@ -3407,10 +3398,10 @@ static int pktgen_thread_worker(void *arg) pr_debug("starting pktgen/%d: pid=%d\n", cpu, task_pid_nr(current)); - set_current_state(TASK_INTERRUPTIBLE); - set_freezable(); + __set_current_state(TASK_RUNNING); + while (!kthread_should_stop()) { pkt_dev = next_to_run(t); @@ -3424,8 +3415,6 @@ static int pktgen_thread_worker(void *arg) continue; } - __set_current_state(TASK_RUNNING); - if (likely(pkt_dev)) { pktgen_xmit(pkt_dev); @@ -3456,9 +3445,8 @@ static int pktgen_thread_worker(void *arg) } try_to_freeze(); - - set_current_state(TASK_INTERRUPTIBLE); } + set_current_state(TASK_INTERRUPTIBLE); pr_debug("%s stopping all device\n", t->tsk->comm); pktgen_stop(t); @@ -3485,8 +3473,8 @@ static struct pktgen_dev *pktgen_find_dev(struct pktgen_thread *t, struct pktgen_dev *p, *pkt_dev = NULL; size_t len = strlen(ifname); - if_lock(t); - list_for_each_entry(p, &t->if_list, list) + rcu_read_lock(); + list_for_each_entry_rcu(p, &t->if_list, list) if (strncmp(p->odevname, ifname, len) == 0) { if (p->odevname[len]) { if (exact || p->odevname[len] != '@') @@ -3496,7 +3484,7 @@ static struct pktgen_dev *pktgen_find_dev(struct pktgen_thread *t, break; } - if_unlock(t); + rcu_read_unlock(); pr_debug("find_dev(%s) returning %p\n", ifname, pkt_dev); return pkt_dev; } @@ -3510,6 +3498,12 @@ static int add_dev_to_thread(struct pktgen_thread *t, { int rv = 0; + /* This function cannot be called concurrently, as its called + * under pktgen_thread_lock mutex, but it can run from + * userspace on another CPU than the kthread. The if_lock() + * is used here to sync with concurrent instances of + * _rem_dev_from_if_list() invoked via kthread, which is also + * updating the if_list */ if_lock(t); if (pkt_dev->pg_thread) { @@ -3518,9 +3512,9 @@ static int add_dev_to_thread(struct pktgen_thread *t, goto out; } - list_add(&pkt_dev->list, &t->if_list); - pkt_dev->pg_thread = t; pkt_dev->running = 0; + pkt_dev->pg_thread = t; + list_add_rcu(&pkt_dev->list, &t->if_list); out: if_unlock(t); @@ -3675,11 +3669,13 @@ static void _rem_dev_from_if_list(struct pktgen_thread *t, struct list_head *q, *n; struct pktgen_dev *p; + if_lock(t); list_for_each_safe(q, n, &t->if_list) { p = list_entry(q, struct pktgen_dev, list); if (p == pkt_dev) - list_del(&p->list); + list_del_rcu(&p->list); } + if_unlock(t); } static int pktgen_remove_device(struct pktgen_thread *t, @@ -3699,20 +3695,22 @@ static int pktgen_remove_device(struct pktgen_thread *t, pkt_dev->odev = NULL; } - /* And update the thread if_list */ - - _rem_dev_from_if_list(t, pkt_dev); - + /* Remove proc before if_list entry, because add_device uses + * list to determine if interface already exist, avoid race + * with proc_create_data() */ if (pkt_dev->entry) proc_remove(pkt_dev->entry); + /* And update the thread if_list */ + _rem_dev_from_if_list(t, pkt_dev); + #ifdef CONFIG_XFRM free_SAs(pkt_dev); #endif vfree(pkt_dev->flows); if (pkt_dev->page) put_page(pkt_dev->page); - kfree(pkt_dev); + kfree_rcu(pkt_dev, rcu); return 0; } @@ -3812,6 +3810,7 @@ static void __exit pg_cleanup(void) { unregister_netdevice_notifier(&pktgen_notifier_block); unregister_pernet_subsys(&pg_net_ops); + /* Don't need rcu_barrier() due to use of kfree_rcu() */ } module_init(pg_init);